200hp, 20mpg, N/A??

[ARRESTmeRed04]

hey yall, my first car was an 81 280zx 2+2 auto, now i'm looking to build one for a DD which is why i want the 20MPG. i'm not looking for monster hp but i'd like about 200 at the crank, and keep the EFI. i'm thinking of using a 3.70 rear out of a 300zx to help with fuel mileage. so how hard would it be to reach these goals?? i was thinkin an N42 head on the F54 block with a cam(not sure which one), header and full exhaust. how is everyone tuning the fuel injection on their cars?? thanks in advance and i'm sure i'll have plenty more questions:biggrin:

[1 fast z]

Possibly with a different head choice. Going to be tough with stock electronics.

[ARRESTmeRed04]

i've been browsing old post, looks like a P90 shave .080" with longer valves is the way to go?? could i use the MegaSquirt with all the factory injectors and sensors? i've never looked at megasquirt at all, i'm gonna search a little bit though

 

would swapping to SU carbs still get my MPG where i'd like to be and reach the 200hp mark? if so that would be an option

[Hyuri]

I have a fairly worn-out stock '83 NA, and flogging it day before yesterday turned in just shy of 19 MPG the first leg and just over 21 the second. About 20 overall for the day then, with an average speed over ~300 miles that I wouldn't admit in court. Ancient plugs/wires, 233k miles, iffy clutch ... if my car can do it, just about anyone's should be able to.

 

Possibly even with 200 HP. Especially if you can keep your foot out of it.

[janaka]

I had an F54 block with a moderate cam, header and 2.5" exhaust with a 5spd and 3.90:1 and I could get 20-25MPG on the highway at 70mph consistantly. I did have SU carb's not FI though, not that that should be a big difference though. I bought the car and from FL all the way to Canada (where I am) in December and I'm pretty sure without checking that I averaged 23~ mpg on that trip. that was with older plugs and unknown milage on the oil. 23hrs of straight driving. The car dyno'd the following fall at 162RWHP/162TQ... Thats 190crank give or take probably depending on who's percentage of drivetrain loss you believe in.

[johnc]

Years ago, when my 240Z was in an autocross configuration (BSP) I was able to do almost exactly what you list above.

 

N42 block 1mm overbore.

N42 head milled to the max OEM limit.

Stock 260 Z "C" cam.

Dished pistons.

SU carbs.

Nissan Motorsports 1 5/8" Headers.

2.5" exhaust.

4 speed.

3:54 gears.

225/50-15 tires on 15 x 8 wheels.

 

185 horsepower, 23 mpg towing a small tire trailer at 70 mph. It would also do the 1/4 mile in 13.9 and do a lap around WSIR in 1:33.xxx.

 

[BRAAP]

My example is similar to Johns, a little more mileage, (I wasn't towing a trailer though), little less performance. Never measured the engine on dyno, guesstimated it between 185-210 crank HP.

 

’75 280-Z, daily driver, ASP autocrosser, (back when Z cars were in A Street Prepared).

2800 lbs with driver and half tank gas.

Recorded 28 MPG several times over the years measured down I-5 using mile posts holding between 60-65 MPH, (I don’t trust Z odometers).

0-60 mph in 5.7 seconds, ¼ mile in 14.4 @ 97 MPH.

Engine;

Mostly stock L-28. ’77 N-47 head, ported myself. Stock N-42 dished piston bottom end. Stock ’77 cam. Stock ’75 EFI. 6-2 Header, true dual 1 ¾” exhaust, no balance pipe. Stock ignition with Jacobs Wires and coil, recurved mech advance. Several years fidgeting with the stock '75 EFI.

Drive train;

Stock open 3.54 R-200 diff, ’77 5 speed trans, stock flywheel lightened myself. 195 60HR 14” tires.

 

 

 

 

 

 

The car then received a mild SBC 350 in ’97, weighed in at 2950 lbs with driver and half tank,

Trans was a W/C T-5 5 speed, welded 3.9 ratio R-200, (way wrong final ratio, 1st gear was useless).

Mileage dropped to a best of 20 MPG, trade off was that it ran consistent 0-60 in 4.2 seconds, ¼ mile in 12.3 @ 113 MPH.

Never measured HP either, guesstimated to be 320-350 crank HP.

[ARRESTmeRed04]

ok thats GREAT news, braap what did you use to tune the factory EFI like you wanted? and maybe my fuel mileage sucked in my 81 because it was an auto?(and i was 16 years old:roll:) but i only got 16-17mpg with it. how about the head?? would the P90 shaved be better than the N42? and would a P79 be any good if it was shaved like the P90?(i'm gonna search for the differances) also since there is no smog check here would an intake with out EGR make any more power? jhonc and braap, thoes are really nice Zs and pretty much what i want to build only with a ZX(just somethin fun to drive to work) my SRT-10 isn't very fun to drive, but then again i've got the suspension set up for drag racing, it was pretty fun stock

[BRAAP]

ok thats GREAT news, braap what did you use to tune the factory EFI like you wanted? ...

Old school baby, All seat of the pants. Tuned the AFM, played with water temp sensor resistance, and lots of miles and gas. Looking back with what I know now, I’ll NEVER go through that much effort tuning again!

If I had an O-2 sensor and a Dyno, could’ve gotten it to that point in much less time.

 

...

how about the head?? would the P90 shaved be better than the N42? and would a P79 be any good if it was shaved like the P90?(i'm gonna search for the differances) ...

As for the head, within your goals, don’t get all wrapped in splitting hairs. It is totally realistic with a simple stock combination whether it is with early dished piston bottom end with N-42 or N-47 head, or later flat top piston bottom end with the P-79 or P90 head to achieve. If you have the time and desire to “tune” it can and has been done. I’ve been able to get comparable results from both combinations within the range you are looking for. If you are wanting more, then juggling heads, pistons, aftermarket cams, aftermarket induction etc is going to add lots of money to the project for a little to moderately more overall horsepower, AND a loss in drivability and mileage.

 

It all boils down “tuning”. Mine and Johns car are examples of what time and persistence can achieve with less than ideal parts, stock smog cams, stock sub 9:1 compression ratios, etc…

 

 

Good luck,

Paul

[Daeron]

Tuning this car with the stock EFI can be done, with pleasant results, but its just barely a step up from tuning a carburetor system.. Its REALLY not that far removed from reprogramming a toilet mechanism. Megasquirt will do you for your power goals, and should tickle you pink for your mileage goals at the same time.

[TrumpetRhapsody]

I'm tickled pink with Megasquirt

 

24+ mpg, city driving and WOT tuning runs.

 

Stock L28 with Stage 1 MSA cam and MSA 6-1 headers.

[ARRESTmeRed04]

Tuning this car with the stock EFI can be done, with pleasant results, but its just barely a step up from tuning a carburetor system.. Its REALLY not that far removed from reprogramming a toilet mechanism. Megasquirt will do you for your power goals, and should tickle you pink for your mileage goals at the same time.

 

if the stock efi can do what i'm trying to get to i'd be fine with it, can you help me out on HOW to tune it, like physically what do i do to it, i tried a search and found the alanticz thing on trouble shooting but nothing about tuning the cars A/F ratio

[Daeron]

Get the EFI bible and learn how to play with electronics. If this tuning is within your grasp, you won't need someone to tell you how to do it. Sorry, thats the reality of it though; BRAAP and I are talking about tweaking the angle the AFM sits at, replacing the CTS with a driver-variable potentiometer, installing a wideband O2 sensor, and dialing in your air/fuel mix on the fly by yourself. Ultimately you decide upon injector sizing/fuel pressure (stock or not.) Really, at this point, MS is probably cheaper, and DEFINITELY will return you far more power and fuel efficiency.

[ARRESTmeRed04]

mega squirt sounds like the way to go then thanks

[BRAAP]

mega squirt sounds like the way to go then thanks

 

YES! I agree, after-market EMS offers so much more flexibility, control, and precision over the OE EFI, it is almost a no brainer. Don't forget, the after-market EMS allows essentially unlimited growth with your project, with cams, intake manifold designs and styles, power adders such as Turbos, Nitrous, blowers, alternative fuels, E-85, etc. After-market EMS allows you to tune without compromise to WOT performance or cruise mileage. The OE EFI is HUGE compromise. The more mods done, the larger the compromise. Also of valuable note. The OE EFI does NOT play well with aftermarket cams AT ALL! Being able to get rid of the AFM from the air stream allows all sorts of freedom in induction routing and removes that restriction from he air stream. Again, aftermarket EMS opens the doors to further power AND mileage gains over what the OE S-30 EFI could ever hope to offer.

 

As to which aftermarket EMS to choose? Depends on many factors. I threw together this quick and dirty EMS primer. Don’t take it verbatim as it is chocked full of my own personal opinions which may not fall inline with your goals and intents, though there should be enough info and links to EMS resources to form your own educated decision on what would best work for you and your application.

 

Here is a listing of the stand alone EMS's…

Click ME for the listing of after-market EMS and the links to those manufactures

 

Also, search through the different EMS sections here on HybridZ.

 

 

Here is my not so humble opinion on a few of the systems.

 

Megasquirt; Low entry cost, very research intensive regarding figuring it out and setting up a lap top and also somewhat sensitive to EMF, so long as you follow tried and tested procedures to reduce the chances of EMF interference, it works fine. Again, MS requires not much money on initial investment compared to the other stand alones, but you must possess a savvy grasp on PC software, (not just knowing how to turn the computer on and surf the web, much deeper PC geek configuration stuff, or at least the desire to want to learn), and also the patience, time, AND ability to SEARCH and RESEARCH many forums, not just HybridZ, but the other Mega Squirt dedicated forums.

 

SDS; A bit more costly than Mega Squirt, probably the simplest in terms of it overall architecture compared to the other available EMS's, not as many fine tuning options as the other stand alones, but its simplicity and over all excellent functionality make it an excellent choice, even for full tilt dedicated race cars.

 

WOLF 3d; in my opinion, the Wolf 3d is one of the better bang for the buck standalone systems with all it is options, controllability, map blending, resolution, number of supported cylinders for distributor-less ignition, etc. Covers everything from stock engines to full tilt Turbo AND Nitrous fed, staged sequential fuel injected, distributor less ignition, V-8’s and everything in between. I ran Megasquirt on my L-28 last year, bought Wolf 3d for my next V-8Z project. Currently running Wolf 3D “Direct Fit” in my ’93 Z-32 and LOVE IT! Saving up for another WOLF-3d System because I like its flexibility, user friendliness and overall functionality “that much!” Sure it cost approx 1/4-1/2 as much more than a MS system, but in my not so humble opinion, that extra cost more than covers the headaches endured tinkering/configuring Megasquirt up to the point of start up, for us mere mortals with mild to moderate PC savvy. Again, that is just my personal opinion.

 

AEM, Haltech, Electromotive; all are well known powerful stand alone EFI systems and each has their strengths, and are all good systems.

 

 

Have fun and good luck.

[ozconnection]

Good solid advice is what we need....and get, thanks!

[ARRESTmeRed04]

braap i was leaning towards the wolf3D also after looking thru some of the post in the EMS section now i'm gonna look at prices

[ktm]

WOLF 3d; in my opinion, the Wolf 3d is one of the better bang for the buck standalone systems with all it is options, controllability, map blending, resolution, number of supported cylinders for distributor-less ignition, etc. Covers everything from stock engines to full tilt Turbo AND Nitrous fed, staged sequential fuel injected, distributor less ignition, V-8’s and everything in between. I ran Megasquirt on my L-28 last year, bought Wolf 3d for my next V-8Z project. Currently running Wolf 3D “Direct Fit” in my ’93 Z-32 and LOVE IT! Saving up for another WOLF-3d System because I like its flexibility, user friendliness and overall functionality “that much!” Sure it cost approx 1/4-1/2 as much more than a MS system, but in my not so humble opinion, that extra cost more than covers the headaches endured tinkering/configuring Megasquirt up to the point of start up, for us mere mortals with mild to moderate PC savvy. Again, that is just my personal opinion.

 

 

You are a more rabid supporter for Wolf than I.